EP2013961A1

EP2013961A1 - Method for producing a bar winding for the stator of an electric machine

Info

Publication number: EP2013961A1
Application number: EP07727908A
Authority: EP
Inventors: Thomas Berger; Christoph Schwarzkopf
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2006-04-26
Filing date: 2007-04-10
Publication date: 2009-01-14
Anticipated expiration: 2027-04-10
Also published as: US8584346B2; US20090100665A1; JP5237933B2; JP2009535009A; CN101432951A; DE102006019312A1; EP2013961B1; CN101432951B; WO2007125010A1

Abstract

The invention relates to a method for producing a bar winding (18) for the stator (16) of an electric machine, especially of a claw pole generator for motor vehicles. Said stator has at least four conducting segments (36) in every coil head (45, 46) which are radially superposed and interconnected in pairs. In this manner, a resistance welding method can be used, the welding current (I) being guided through the ends (42) of the conductor pairs in a partially radial and in a partially axial manner in relation to the rotor axis (27) in the fusion zones (40).

Description

description

title

Method for producing a bar winding for the stator of an electrical machine

State of the art

The invention relates to a method for producing a rod winding for the stator of an electrical machine, in particular a claw pole generator for

Motor vehicles, as has become known from DE 40 31 276 A in principle. This document discloses a method for producing a stator for electrical machines, whose rod winding is made of four paired in the grooves superimposed winding wires, which are pre-bent haarnadelformig and plugged with a spreading step of a pole pitch in the laminated core grooves. The ends of the winding rod are interlocked on both sides of the laminated core against each other and galvanically connected to one side of the laminated core in pairs by welding or soldering. The document makes no detailed information about the connection method used for the ends of the winding rod.

Disclosure of the invention

The inventive method offers over the prior art, the possibility of using the fundamentally known method of resistance welding even with winding arrangements with four or more superimposed conductor segments and the case remaining very small working space for the necessary connections with low manufacturing complexity mechanically and electrically secure and durable connections in the winding head of the stator produce. In this case, in particular in the case of an arrangement with four conductor segments arranged radially one above the other in the winding overhang, particularly advantageous configurations result both with regard to the arrangement of the rod ends and with regard to the design of the welding electrodes.

A very simple and advantageous method is to produce the electrical connections at the same time or successively through two electrodes in the winding over each other radially by one conductor segment of each pair radially and at least one conductor segment axially contacted by an electrode and the welding current in this case by 90 ° is deflected.

Expediently, in this case the outer conductor segments of two conductor pairs to be connected are each contacted by a separate, radially operating electrode and the two middle conductor segments by a common, axially operating electrode. This procedure is particularly advantageous when the ends of the inner conductor segments of two pairs of conductors further protrude from the laminated core of the stator than the outer conductor segments, because the inner conductor segments are then better accessible and this also a wear-resistant

Electrode with a larger cross-section can be used. In addition, this procedure offers the possibility without mechanical reworking far different from the laminated core of the stator outstanding ends of the inner Conductor segments first melt through the electrode to the same length and then contact together.

A particularly advantageous embodiment of the inventive method is obtained when the ends of the inner conductor segments of two pairs of conductors further protrude from the laminated core of the stator than the outer conductor segments and all conductor segments are contacted radially from the electrodes during the welding process. This procedure offers the particular advantage that the

Welding process no axial forces acting on the conductor segments and the radial forces can be fully absorbed without additional mechanical locking of the welding electrodes.

The inventive method is advantageously applicable even in an arrangement with more than four, for example, six radially superposed in the winding over each other and to be connected in pairs conductor segments by either the ends of all pairs of conductors during the welding process are axially contacted by the electrodes. Instead, however, the outer conductor segments of the outer conductor pairs to be connected can each be contacted by a radially operating electrode, in turn, the radially operating electrodes absorb the forces acting in the radial direction in the welding process, so that only the axially acting forces collected by a separate jig Need to become.

Brief description of the drawings

Exemplary embodiments of the invention are illustrated in the drawings and explained in more detail in the following description. Show it 1 is a perspective view of a stator with a bar winding with preformed for the welding process ends of the conductor segments,

2 is a partial section through the laminated core of the stator with radially extending grooves, each with four superimposed conductor segments,

3a is a schematic sectional view with four in the winding head of the stator superimposed, pairwise welded conductor segments,

3b is a schematic representation of a wave winding with a welded connection of a conductor pair,

4 shows an arrangement with four radially arranged in the winding over each other and to be connected in pairs, equally long conductor segments,

5 shows an arrangement with four conductor segments arranged radially one above the other in the winding head and to be connected in pairs, wherein the two middle segments continue to protrude from the laminated core of the stator than the outer segments,

Fig. 6 shows an arrangement according to Figure 5 with only radial contacting of the ends of the conductor segments and Fig. 7 shows an arrangement with six radially in a groove and in the winding over each other and arranged in pairs interconnected conductor segments.

Embodiments of the invention

Fig. 1 shows a perspective, schematic representation of a stator 16 of an electric machine, as used for example in a Klauenpolgenerator for motor vehicles. On the inner surface of the stator 16 are poles 32 and grooves 34 can be seen, in each of which four conductor segments 36 are arranged radially one above the other. The conductor segments are bent in a known manner on the underside of the stator 16 haarnadelformig and bounded in each case one pole pitch. Their equally long, free ends 42 protrude at the top of the stator 16, also limited by a pole pitch, out of the grooves 34 and are arranged in four concentric rows. In this case, after assembly of the electric machine, the free ends 42 in the drive-side winding head 45 of the stator, while the haarnadelformigen deflections 44 protrude at the opposite end winding 46 of the stator 16, which is aligned to the assembly side of the electrical machine to the wiring side. This arrangement has the advantage that 45 more space for the welded joints is available in the drive-side winding head. The machine axis is designated 27.

Fig. 2 shows an enlarged view of a section through the laminated core 17 of the stator 16, wherein in each groove 34 four conductor segments 36 are arranged radially one above the other. The conductor segments are on the one hand on their surface by a paint insulation 38 and on the other hand together insulated by insulating inserts 39 against the laminated core 17 of the stator 16. The introduction of the conductor segments 36 of the stator winding 18 designed as a bar winding takes place by axial insertion of the conductor segments 36 into the grooves 34.

Fig. 3 shows in the figure a in schematic form a partial section through the laminated core 17 of the stator 16, from which the free ends 42 of the stator winding 18 protrude. The ends 42 of the stator winding 18 are freed from the lacquer insulation 38 in the front region 43, so that the welding current in this region can flow both radially and axially unhindered and can melt a welding region 40. Between the non-welded ends 42 of the conductor segments 36, a distance d is left, in addition, a band-shaped insulation 48 can be introduced, for example, a plastic or ceramic tape.

FIG. 3 b shows the hairpin-shaped deflection 44 between the conductor segments 36 in the area of the winding head 46 facing away from the drive side, the spreading of the conductor segments 36 about a pole pitch and the clogging of the free ends 42 towards the welding regions 40. The inventive welding of the ends 42 with the various possibilities of designing the welding electrodes and the arrangement of the ends 42 in the welding region 40 will be discussed in more detail with reference to the following figures.

Fig. 4 shows an arrangement with four in the drive-side winding head 45 radially superimposed and pairwise welded together conductor segments 36 whose stripped ends 43 equidistant from the laminated core 17 of the Stators 16 protrude and end at the same height in the winding head 45. The individual conductor segments 36 are denoted by I, II, III and IV, wherein the conductor segments I and II, or III and IV are welded together in the area 40. Between the conductor segments II and III insulation 48 is inserted. The conductor segment I is radially contacted by the negative welding electrode -El, the conductor segment II on its end face axially through the positive electrode + El. Here, the welding current I flows from the electrode -El first radially through the

Conductor segment I and then reverses its current direction in an axial direction to the positive electrode + El. In this way, the conductor segments to be welded I and II and in the same way the conductor segments III and IV without difficulty by sufficiently massive and therefore permanent welding electrodes are contacted, which have the necessary life in production. At the same time take the electrodes -El in the radial direction from the outside and + El in the axial direction of the winding head side according to the arrows 50 and 52, the clamping forces for the positioning and locking of the conductor segments 36 during the welding process. From the stator 18 and from the inside of the winding head must according to the arrows 54 and 56 by not shown mechanical auxiliary equipment, the Anpresskrafte

Welding to be caught. The spatial orientation of the arrangement according to FIG. 4 is indicated, as in FIGS. 5 to 7, by the central axis 27 of the machine.

Fig. 5 shows an arrangement with also four, in the drive-side winding head 45 radially superimposed and pairwise welded together conductor segments 36, wherein the two middle segments II and III further protrude from the laminated core 17 as the outer segments I and IV. The contacting of the conductor segments I and IV takes place respectively in the radial direction through the electrode -El from the outside and the electrode -E2 from the inside, the conductor segments II and IV are by a common electrode + E in the axial direction of of the

Front side of the conductor segments 36 ago contacted. In this case, the welding current I flows from the negative electrodes -E1 and -E2 initially in the radial direction through the conductor segments I and IV and in turn becomes positive in the region 40 of the welds in the axial direction

Welding electrode + E deflected. The welding of the two conductor pairs I and II, or III and IV can be carried out simultaneously, which are compensated by the positive electrode + E possibly existing unequal axial lengths of the two conductor segments II and III by a longer conductor segment, as indicated in the segment III is first melted by the electrode, before the two conductor segments II and III contacted together and the welds 40 are made. In this arrangement, the mechanical locking forces must be absorbed during the welding process only in the area of the laminated core 17 according to the arrow 54, the remaining positioning and locking forces 50, 52 and 56 are applied without additional structural measures by the electrodes themselves.

The joint contacting of the conductor segments II and III by a single electrode + E, as shown in Fig. 5, is also used in the arrangement of FIG. 4 for common contacting of the middle conductor segments II and III. In this case, the negative electrode -El could be converted to the conductor segment IV or it can also be applied in this design for contacting the conductor segment IV, an additional negative electrode -E2. Any existing differences in length of the conductor segments 36 can then be compensated by melting in the arrangement of FIG. 4 and / or the welding process for both pairs of conductors are performed in one operation.

6 shows the same configuration of the conductor segments 36 as in FIG. 5. However, four separate electrodes -E1 / + E1 and -E2 / are used to make contact with the ends 43 during pairwise welding of the conductor segments I and II on the one hand and the conductor segments III and IV on the other hand. + E2 only applied radially. The welding current I is in this case twice deflected from a radial to an axial and then again in a radial direction, all conductor segments are well accessible and the arresting forces occurring solely in the radial direction for the conductor segments are taken up exclusively by the welding electrodes according to the arrows 50.1 and 50.2 and 56.1 and 56.2. Axial forces on the conductor segments 36 do not occur in this configuration.

Fig. 7 shows an arrangement with six in the drive-side winding head 45 radially superimposed conductor segments I-VI, which in turn are connected with the insertion of insulation 48 at their free and stripped ends 43 in pairs in the welds 40 with each other. For the arrangement of the welding electrodes -E and + E different possibilities are shown schematically, wherein the outer conductor segments I and VI are preferably contacted by radially attached welding electrodes -E. However, these conductor segments I and VI can also be contacted axially, as shown for the remaining conductor segments II, III, IV and V. Another alternative not shown would also be here corresponding to FIGS. 5 and 6, if, for example, the Conductor segments IV and V are axially extended and radially or axially contacted. When using radially applied welding electrodes -E can in turn the radial Arretierungskrafte 50 and 56 are collected during welding, with axial contacting individual or all conductor segments from the side of the laminated core 17 forth the required positioning and locking forces according to the arrow 54 by suitable Clamping means for the laminated core 17 are collected.

Electrical machines, in particular Klauenpolgeneratoren for motor vehicles, with a stator winding 18 in rod or Steckwickstechnik have a very good ventilation of the winding heads 45 and 46 and generate even at high speeds only a relatively low noise. The proposed measures result in the production of such stators 16 significant manufacturing advantages, since the welding processes are significantly facilitated and improved, so that in many applications, the very advantageous resistance

Welding process is made possible in the first place. In addition, mechanical locking and positioning means can be largely or even completely saved and exposed to high wear electrodes correspondingly solid and therefore durable, if according to the invention, the arrangement is made such that the current flow direction and the direction of the force to be applied during the welding process at least partially be separated from each other. The axial equalization of the arrangement of the conductor segments 36 thereby additional space for the design and accessibility of the welding electrodes is created. The possibility of using robust and large-sized welding electrodes additionally facilitates the feeding of higher welding currents I, resulting in shorter contacting times with less heating, so that the insulation of the conductor segments 36 is less at risk due to the effects of heat. In the welding area, contacts between adjacent conductor segments can be reliably avoided by additional insulations of insulation elements 48 removed after the welding, so that faulty contacts between the conductor segments 36 do not occur in the welding zone. In addition, the insulation 48 by suitable choice of material, for example by choosing a suitable plastic or ceramic, take over the power transmission in the middle conductor segments.

Claims

claims

1. A method for producing a rod winding (18) for the stator (16) of an electrical machine, in particular a Klauenpolgenerators for motor vehicles, each with at least four in the winding head (45,46) arranged radially one above the other and connected in pairs conductor segments (I-IV; 36), wherein the ends (42) of the conductor segments (I-IV; 36) are connected by resistance welding and in this case the welding current (I) in the ends to be connected (42) of the conductor pairs (I, II, III, IV) partially radially and partially axially relative to the machine axis (27).

2. The method according to claim 1, characterized in that of two conductor pairs to be connected (I, II, III, IV) each have a conductor segment (1, IV) radially and at least one conductor segment (II, III) axially of an electrode (± E ) is contacted (Figures 4 and 5).

3. The method according to claim 1 or 2, characterized in that the outer conductor segments (1, IV) of two conductor pairs to be connected (I, II, III, IV) each of a separate, radially operating electrode (-El, -E2) and the two middle conductor segments (II, III) are contacted in common by an axially operating electrode (+ E) (Figure 5).

4. The method according to any one of the preceding claims, characterized in that the ends of the inner Conductor segments (II, III) of two pairs of conductors (I, II, III, IV) further from the laminated core (17) of the stator (16) protrude than the outer conductor segments (I. IV) and jointly contacted by an electrode (+ E) (Fig. 5).

5. The method according to claim 4, characterized in that far different from the laminated core of the stator (16) outstanding ends (42) of the inner conductor segments (II, III) after melting the Uberstandes a longer end by a common electrode (+ E) be contacted (Fig. 5).

6. The method according to claim 1, characterized in that the ends (42) of the inner conductor segments (II, III) of two conductor pairs (I, II, III, IV) further from the

Sheet metal stack (17) of the stator (16) protrude than the outer conductor segments (1, IV), and all conductor segments (I-IV) during the welding process radially from the electrodes (± E1, ± E2) are contacted (Fig. 6).

7. The method according to claim 1, characterized in that the ends (42) of all conductor segments (I-VI) of the conductor pairs

(I, II, III, IV, V, VI) are axially contacted by the electrodes (± E) during the welding process (Figure 7).

8. The method according to claim 1, characterized in that the ends (42) of the outer conductor segments (1, VI) of the conductor pairs to be connected (I, II, III, IV, V, VI) in each case by a radially operating electrode (- E) and the middle conductor segments (II-V) are in each case contacted by an axially operating electrode (± E) (FIG. 7).

9. The method according to any one of the preceding claims, characterized in that the ends to be joined (42) the conductor segments (I-VI) are arranged with axial electrical contact with one another and are mechanically positioned and held in the welding process by the electrodes (+ E) at least in the radial direction (50, 54).